Condensation of formaldehyde with urea and phenylthiourea



Patented Feb. 394% an entree CGNDENSA'KIQN 09F FORMAEDEHWE WIITH "UREA AND PHENYLTHEQUEEA Hans lilJchse and Rolf Riiber, Dortmund, Germany No Drawing. Application May .llil, 1938, Serial No. 206,997. In Germany May 13, 1937 ll Claim.

It has already been proposed to-act with formaldehyde on urea and thiourea in order to obtain artifcial substances accessible to hardening and fit for being employed as equivalents forhom, amber and other similar natural products.

Now it has been found that mixtures of urea and phenyl thiour'ea may be condensed very advantageously to similar artificial substances of excellent mechanical properties. This is surprising since, as results from 10 thiourea when employed alone yields condensation products which remain glutinous or greasy even after a longer treatment in vacuo, being therefore unfit as equivalents for the above named natural products. vMoreover the employment of phenyl thiourea shows the advantage that it may be prepared by simple condensation of ammonium thiocyanide with hydrochloric aniline. In this way a fundamentally new sphere of employment is opened to the ammonium thiocyanide obtained on the distillation of coal in enormous quantities and only hard to utilize. The employment of phenyl thiourea offers the further advantage that the water'solubility of the condensation product so obtained is exceedingly diminished, probably by the introduction of the phenyl group. This is expressed by the exceedingly high surface resistance of products filled with wood powder which still amounts even after storing in water to about 140,000 o. The addition '30 of urea cannot be completely omitted in that the literature, phenyl' (CL Wit-89) otherwise no products capable of hardening are obtained. However, the urea may be partially replaced by other substances reacting with formaldehyde such as phenol, thiourea, aniline and the like. The new process may be explained by r the following example: 0 152 parts (by weight) phenyl thiourea and 120 parts urea are dissolved in 480 parts formaldehyde (aqueous solution of 41%). 18 parts hexamethylenetetramine are added and the whole mixture is now heated during 10 to minutes 10 to about -95 C. Now the water is distilled off in vacuo. A syrupy glutinous liquid remains which grows hard on further heating. On heating to about 80 C. during 6-8 hours a resin is obtained which may. be easily pulverized after 15 cooling. The compressible powder so obtained may be worked up without any trouble in heated press-devices of usual construction, and, what is more, alone or mixed with the usual colouring materials, softening substances or filling mate- 20 rials such as wood powder, asbestos, linen, cotton, paper etc.

We claim:

In the method of producing condensation products the improvement which consists in heating 25 urea, m'onophenyl thiourea. and formaldehyde in the presence of substances which act as condensing agents.

HANS DOHSE.

new Roam. so 

